Tag Archives: Lesotho

Technology solves disappearance mystery of one of Africa’s famous birds

The mystery of the gradual disappearance of the Bearded Vulture, one of Africa’s most famous birds, has been solved using the technology of satellite tracking.

Once widespread throughout much of Southern Africa, the Bearded Vulture is now critically endangered, with a decline in nesting sites of nearly 50 per cent since the 1960s.

The remaining population is now restricted to the Drakensberg mountains in Lesotho and South Africa. But even in these isolated mountains they continue to decline.

Satellite trackers attached to 18 Bearded Vultures have confirmed conservationists’ worst fears: humans are largely to blame with collisions with power lines and poisoning being the two major vulture hazards that killed half of the birds in the satellite tracking survey.

These are key findings contained in two new research projects published this month. The studies paint the most detailed picture to date of the challenges facing the Bearded Vulture, also known as the ‘bone breaker’ due to its habit of dropping bones from a height to feed from the marrow inside.

Lead author on the study Dr Sonja Krueger says: “We explored where the biggest difference lay between abandoned and occupied territories and found that human related factors such as human settlement density and powerlines were consistently different between these sites.”

Power line density and human settlement density were more than twice as high within abandoned vulture territories compared to occupied territories, the study found.

By contrast climate change was not found to be a major contributing factor in nest abandonment.

“Though not definitive, the results strongly suggest that we humans are our own worst enemies when it comes to conserving one of Africa’s iconic birds,” Krueger says.

The study recommended a new approach to vulture conservation management: “Based on the identified threats and mechanisms of abandonment, we recommend that conservation management focus on actions that will limit increased human densities and associated developments and influence the attitudes of people living within the territories of (vulture) breeding pairs,” the study concluded.

“We recommend that mitigation of existing power lines, stricter scrutiny of development proposals, and proactive engagement with developers to influence the placement of structures is essential within the home range of a territorial pair.”

The trackers not only showed the exact location of the tagged birds every hour, they also provided critical information on movement patterns and mortality.

Tagging enabled dead birds to be quickly recovered and their cause of death determined.

The study confirmed that, in addition to power lines, poisoning was considered the main threat to vultures across Africa and was contributing to the so-called “African Vulture Crisis”– a large decline of many vulture species across the continent.

The tracking data also provided new information about the birds’ ranging behaviour. It revealed that non-breeding birds traveled significantly further than breeding birds and were therefore more vulnerable to human impact.

Some young non-breeding birds patroled an area the size of Denmark. The average adult bird had a home range of about 286 sq km, but the range was much smaller for breeding adults at just 95 sq km.

Dr Arjun Amar from UCT said detailed knowledge about Bearded Vulture home ranges could be hugely beneficial to vulture conservation: “We knew the species was likely to have large home ranges, but our results show just how far these birds travel – and therefore how exposed they are. The more they travel, the more they risk colliding with power lines or falling prey to poisoning.”

In a report published in the scientific journal Conservation Letters, scientists from across Africa, Europe, and North America have published the first continent-wide estimates of decline rates in African vultures: and find that many national parks and game reserves appear to offer vulture species in Africa little effective protection: here.

Vultures, such as the Vulnerable Cape VultureGyps coprotheres, have a higher risk of collision with wind turbines. Thus appropriate assessment of the collision risk to these species must inform the decision as to whether the site is suitable for development.

BirdLife South Africa and BirdLife International are very concerned that the proposed development of a wind farm at Letseng in Lesotho could have severe impacts on the already declining populations of Cape Vultures and Lammergeiers. South Africa and Lesotho share the responsibility of safeguarding the populations of Lammergeiers and Cape Vultures in the Lesotho Highlands and the surrounding escarpment of South Africa.

PowerNET Developments (Pty) Ltd propose to erect 42 wind turbines (each with a capacity of 850 kW) near Letšeng-La-Terae, on the north-eastern escarpment of the Drakensberg. The environmental impact assessment (EIA) for the proposed Letseng Wind Farm is in its final stages of completion. The avifaunal specialist report, compiled by well-respected ornithologist Dr Andrew Jenkins, indicates that even with mitigation, the anticipated impacts of the project on highly unique and sensitive avifauna will be of high to very high negative significance, rendering the project unsustainable.

While wind energy is fairly new to southern Africa, poorly located wind turbines elsewhere in the world have had significant impacts on bird populations. Impacts include loss of habitat, disturbance and mortality through collisions with the turbine blades. In Smøla, Norway, for example, wind farms caused the local population of White-tailed Eagles (also known as Sea Eagles) to plunge by 95% – reducing the number from 19 eagle pairs to only one pair.

Such devastating impacts have not occurred at all wind farms. “The considered location of wind farms is the key to ensuring that impacts on birds are kept to a minimum”, says Samantha Ralston, Birds and Renewable Energy Manager for BirdLife South Africa. Among other things, turbines should be kept well away from areas frequently used by collision-prone birds such as large-bodied raptors.

Collision-prone vultures cannot observe political boundaries

Vultures play an important ecological, economic, cultural and aesthetic role. They are scavengers and by disposing of waste and carcasses they help control populations of other disease-carrying scavengers and pests. In this way they help protect human health, as well as that of domesticated animals and wildlife.

Unfortunately, vultures appear to be particularly prone to colliding with the turbine blades. High collision rates have been observed in Griffon Vultures at wind farms in Europe, most notably in Tarifa, Spain. The Griffon Vulture is a close relative of the Cape Vulture. A recent study in Tarifa, Spain, estimated that 0.22 vulture deaths occurred per turbine per year. This was reduced by approximately half with the introduction of mitigation, but even with mitigation one can expect that for every 10 turbines at least one vulture will be killed every year.

The proposed Letseng wind farm is located in habitat that is critical for both Lammergeier and Cape Vulture, both threatened species. Lammergeier is listed as regionally Endangered and Cape Vulture as Vulnerable in South Africa. Birds do not observe political boundaries and the populations of both species span South Africa and Lesotho. A further decline of birds in Lesotho, will severely impact the viability and survival rates of the vultures in South Africa. Using population models, scientists have demonstrated that even a small increase in adult mortality could cause the rapid decline and even local extinction of these long-lived, slow-breeding birds. “BirdLife South Africa has learnt from its partners in Europe and North America that incorrectly located wind farms can cause massive mortalities of vultures and eagles”, says Mark Anderson, CEO of BirdLife South Africa. “For this reason, we will strongly oppose any wind farm developments which we believe will result in significant impacts on Lammergeier, Cape Vulture and other threatened South African birds”, he added.

Responsible sustainable development must be consultative

BirdLife South Africa fully recognises the need to move towards generating clean energy and supports the responsible development of a renewable energy infrastructure in southern Africa. BirdLife South Africa therefore encourages wind farm developers to work with them to help identify suitable sites for wind energy to minimise the impact on birds and the environment while delivering lasting sustainable development. For example, prior to siting a wind farm, a Strategic Environmental Assessment should be undertaken as this enables avoidance of areas that are known to be environmentally sensitive.

Dr Julius Arinaitwe, BirdLife International’s Regional Director for Africa says development is vital, but must progress in an environmentally sensitive manner. “Development is underpinned by healthy ecosystems and the biodiversity therein. The choices we make now must not negatively affect Africa’s ability to develop in future”, he said.

BirdLife South Africa and BirdLife International are calling on PowerNET Developments (Pty) Ltd to voluntarily withdraw the EIA application. BirdLife South Africa is also encouraging the public and partners to comment on the EIA report. Further information can be obtained from Samantha Ralston (at energy@birdlife.org.za or 083-6733948).